CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain.
Catalan Institute of Nanoscience and Nanotechnology (ICN2) , CSIC and The Barcelona Institute of Science and Technology , Campus UAB , 08193 Bellaterra , Catalonia , Spain.
Nano Lett. 2019 Feb 13;19(2):1074-1082. doi: 10.1021/acs.nanolett.8b04368. Epub 2019 Jan 14.
Graphene is an excellent material for long-distance spin transport but allows little spin manipulation. Transition-metal dichalcogenides imprint their strong spin-orbit coupling into graphene via the proximity effect, and it has been predicted that efficient spin-to-charge conversion due to spin Hall and Rashba-Edelstein effects could be achieved. Here, by combining Hall probes with ferromagnetic electrodes, we unambiguously demonstrate experimentally the spin Hall effect in graphene induced by MoS proximity and for varying temperatures up to room temperature. The fact that spin transport and the spin Hall effect occur in different parts of the same material gives rise to a hitherto unreported efficiency for the spin-to-charge voltage output. Additionally, for a single graphene/MoS heterostructure-based device, we evidence a superimposed spin-to-charge current conversion that can be indistinguishably associated with either the proximity-induced Rashba-Edelstein effect in graphene or the spin Hall effect in MoS. By a comparison of our results to theoretical calculations, the latter scenario is found to be the most plausible one. Our findings pave the way toward the combination of spin information transport and spin-to-charge conversion in two-dimensional materials, opening exciting opportunities in a variety of future spintronic applications.
石墨烯是一种远距离自旋输运的优异材料,但自旋操控能力较差。过渡金属二硫属化物通过近邻效应将其强自旋轨道耦合印刻到石墨烯中,并且已经预测,由于自旋霍尔和拉什巴-艾德斯坦效应,可以实现高效的自旋到电荷转换。在这里,我们通过结合霍尔探针和铁磁电极,在实验上明确地证明了 MoS 近邻诱导的石墨烯中的自旋霍尔效应,并且温度范围从室温到室温。自旋输运和自旋霍尔效应发生在同一材料的不同部分这一事实导致了迄今为止尚未报道的自旋到电荷电压输出效率。此外,对于单个基于石墨烯/ MoS 异质结构的器件,我们证明了叠加的自旋到电荷电流转换,可以与石墨烯中的近邻诱导的拉什巴-艾德斯坦效应或 MoS 中的自旋霍尔效应不可区分地相关联。通过将我们的结果与理论计算进行比较,发现后一种情况是最合理的。我们的发现为二维材料中的自旋信息传输和自旋到电荷转换的组合铺平了道路,为各种未来的自旋电子应用带来了令人兴奋的机会。